Nonlinear consolidation of dredged slurry treated by PHDs incorporating development process of elliptical clogged zone

Clogging phenomena have been observed during the consolidation of dredged slurry treated with prefabricated horizontal drains (PHDs) in conjunction with vacuum preloading (VP). Previous studies indicate that the clogged zone exhibits an elliptical shape, with its extent gradually expanding over time. This study proposes a nonlinear consolidation model for PHDs-VP-treated dredged slurry, incorporating the development of the elliptical clogged zone surrounding the PHDs. The governing equations are established, and numerical solutions are derived using the finite element method. The accuracy and applicability of the model are validated through degradation analysis and comparisons with experimental results. Subsequently, a parametric analysis is conducted to assess the influence of key factors on consolidation, including the clogging effect, PHD layout ratio, slurry layer thickness, and soil nonlinear characteristics. The results demonstrate that the clogging effect significantly slows the consolidation rate, with the impact becoming more pronounced as the severity of clogging increases and the clogged zone develops more rapidly. Increasing the PHD layout ratio or reducing the slurry layer thickness effectively accelerates consolidation. However, once the layout ratio surpasses a critical threshold, further increases yield only marginal effects. Additionally, the optimal layout ratio decreases with increasing slurry layer thickness, and relevant engineering recommendations are provided. Furthermore, the consolidation rate decreases with a higher compression index but increases with a higher permeability index.